SFN-20240108F Replace intake airtube

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TICO Document #: SFN-20240108F (formerly TES 162)

Description of Procedure: Vendor manufactured MAF air intake tube incorrectly. Replace 620489 Air Intake Tube-MAF, with correctly made part

Units Affected: S/N 4507-4530 UPS-PSI CNG Engines

Parts Required: 620489 (QTY 1)

Planned Labor: 15 Mins

Instructions:

  1. Park the vehicle on a flat surface, apply the parking brake, and chock wheels. If your company utilizes a “Lock Out, Tag Out” policy, you should employ it during this procedure.

  2. Raise cab to full up position and ensure cab safety bar is engaged on support.

  1. Locate the MAF air tube on the top forward part of the engine. Loosen the two constant torque clamps on the elbows and slide them back on the elbow. Also loosen the clamp on the elbow connected to the air intake tube on, RH side of the frame.

  1. Remove the electrical connector from the MAF sensor. Remove the quick disconnect coupling airline from the nipple on the tube. (See attached picture #1)

  1. Take the air intake elbow off of the frame rail-mounted air tube. This will allow you to remove the MAF tube from the engine-mounted elbow without disturbing the engine intake elbow. Remove the MAF tube from the elbow you just removed. (See attached picture #2).

  1. Install a new MAF air intake tube in the engine-mounted elbow. Check the insertion of a tube into the engine elbow. There is a screen diffuser in one end of the tube. That end of the tube should be on the air cleaner end of the tube (See picture #3 & #4).

  1. Place the loose elbow on the MAF tube and on the frame-mounted tube. Insert the tube into engine mounted elbow. Align the tube with the MAF sensor on top of the tube. Position and tighten the constant torque clamps to 125 in/lbs.

  1. Connect the electrical connector to the MAF sensor, and connect the quick disconnect coupling airline to the nipple on the tube. You should note that the MAF sensor is now pointing in the opposite direction from the old tube. The wire connector should be pointed toward the rear of the truck.

  1. Remove “Lock Out, Tag Out” plaque.

  1. Return vehicle to service.